Lamp, &amp;c.



No. 841,799. y PATENTED JAN. 22, 1907.

' G.'MARIS.

LAMP, 5w.' APPLICATION FILED APR. 1 0. 1905.

UNTFB- STATES-l PATENT. UFFCE.

suonerie MARIS, or PARIS, FRANCE, AssIGNoR To LA socir BnsNAan,A

MARIS a ANTOINE, or PARIS, FRANCE.

LAMP, ae, l j

apprenante@ Aprilia, 1965. sentirti. 254,733. n j j T0 @ZZ whom, itfit/.ty concern: u

Be it known that l, Gnoneiis MARIS, a citizen of the French Republic,residing at Boulevard Beaumarchais, Paris, France, have invented certainnew and useful .lmprovements in Lamps or Devices for Projecting Light;and. l do hereby declare the following to be a full, clear, andexact-description of the invention, such will enable others skilled inthe art to which itrappertains to make and use the same.

This invention consists in the employment of an optical system inconnection with lamps used for projecting, under certain conditions, therays proceeding from a source of light.

The following description shows, by way of example, the manner ofapplying this system to a projector containing an acetylene-gas flameand intended for 'automobile-vehicles, locomotives, boats, te., With theobject of lighting the route to be traveled over to a' sufflicientextent infront and to right. and .e t. I

ln the accompanying drawings, Figure 1 is the front view of a projector;Fig. 2, a section of the same. Figs. 3, 4, and 5, are diagramsillustrating the o )tical system.

l is an acety ene-gas flame arranged between a lens 2 and a reflector 3placed behind the llame.

This invention. is essentially distinguished by the combination of alens and a reflector forming, with the source of light l, an opticalsystem diagrammatically illustrated in Fig. fi.

The lens 2 is a converging plano-convex lens, the focus of which is atF.

The reflector 3 is in the form of a hyperboloid, the meridian section ofwhich is the hyperbola 72r 7L', the focus of which, on the one hand, isin the point F, which is common to the. lens, and, on the other hand.,in thefpoint A the geometrical center of the flame on the axis a: y ofthe projector.

in examining Fig. 3 it will be seen that all the luminous raysproceeding from the point A and comprised in the pencil of rays h Ahh"are reflected by the 4hyperbolic reflector in the form of a conicalpencil of rays the apex of which is the point F, the virtual focusof thehyperbola. The reflected pencil of rays `comes onto the lens as if it.proceeded from a luminous point placed at. F. Under these conditions, Inaccordance with the proper tieso'f the convergmg lens, all the rays ofthis pencil of. rays are lrefracted parallel to proceedingI from thepoint yA and directly reaching the lens are refracted therebyand` inissuing therefrom form a more condensed pencil of rays than the initialpencil of ,I'aysh This refracted pencil of rays has its apex ,in thepoint c, which is` in conjunction with the: point VA in relation to thelens. As the point c is always behind the point A, the intensity of thepencil of rays projected outside is much greater under this system. Thisconical and powerful pencil of rays is intended to effectively light theroute near the rojector and over a larger extent than that ighted by thefirst pencil of rays intended for lighting at a distance. Y Thehyperbolic form can only be obtained with suflicient precision by meansof metallic reflectors; but when acetylene is employed as a source oflight the metallic reflectors are soon tarnished. The hyperbolicmetallic reflectors may be replaced by a spherical mir ror, Fig. 4, thereflecting-surface of which is protectedagainst external changes. Themeridian section of this surfaceis an arc of 'a circle which coincideswith the hyperbolic arc.

and proceeding from the incident raysissuing from the point A inclose avirtually caustic surface, the meridianof which is a curve n mp.

if the focal distance of the lens be so determined that its focus F issituated in the interior of the apex of the caustic surface and' at adistance slightly removed from the tangents to this caustic surface, thepencil of rays refr-acted by the lens will be sufficiently cylindricaland homogeneous. The aberrations, which, `moreover, are but slight, areutilized for illuminating the route in thel diratented Jansz, 1907.

j Iii Vthis case the extensions of the rays lreflected by the sphericalconcave surface rection of its width. These aberrations do not diminishthe range in the distance, which is insured by the employment of thehyper! bolic refiector, as account must be taken of the superiorreflecting and uniform power of IOC the optical mirror compared withthat of mej tallic reflectors and of the practical difliculf sphericalmirror is much more simply kept up an such a system frnished with ametallic reflector, Whichis with diflicnlty in a polished condition.

The casing which forms-the body of the preserved 'pro`ector and connectsthe back reflector -Wit the lens may be of a, form suited to the purposeof the projector.

the rays parallel to the exis x y. In this cese the projector may be'formed in front by en annular glass plate 5, through which the rays ycan pass.' The lens 2, combined with they 'mirror 3, isset in the centerof the glass plate for the purpose of forming the optical system thatdistinguishes this invention.

' What I claim, and desire to secure by Letters Patent, is-

A light-projector for eutomobiles and the like, distinguished bythecombination of a hyperbolic reflector with e converging lens having a,focus in cornmon with the external focus of the reflector', the sourceof light beT ing placed in the internal focus of the hyper# bolicreflector between the re-Hector and the lens, for the purpose described,

In testimony whereof I have affixed inyv signature in presence of twowitnesses.

GEORGES MARIS.

Witnesses:

CHARLES FABER, HENRI GABY.

